數位影像廣播地面波接收器基頻訊號處理演算法實作

Implementation of the DVB-T Receiver For Baseband Processing Algorithms

王經文(Ching-Wen Wang)

指導教授 ： 曾恕銘

國立臺北科技大學/電資學院/電腦與通訊研究所/碩士(2007年)

摘要

近年來，正交分頻多工(OFDM)調變技術在通訊系統上，已經成為受歡迎的調變技術。由於這項技術能夠在有限的頻寬內提供較高的資料傳輸速度，且在符號間干擾(ISI)的通道環境下，它能夠藉由保護區間(Guard Interval)能達到較高的效能，再加上數位信號處理(DSP)技術的提升，使得OFDM調變技術被廣泛的應用在各個通訊系統，如：數位音訊廣播(DAB)、數位電視廣播(DVB)、無線區域網路(WLAN)、等…..。
在過去，大多數有關DVB-T系統的研究是使用硬體來實現，且通道為模擬的通道來做效能的分析。只有少數的研究是用實際環境且用軟體來去實現。這邊我們將繼續延用實驗室留下來的DVB-T基頻性號處理的MATLAB程式，將原先通道估計的內挿方式做改良以提高演算法的正確性，以及在計算維特比解碼時，考慮通道狀態的資訊(Channel State Information)以提升原本維特比解碼器的更正能力。在最後將提出一些想法，可作為未來改善此程式效能的方法。

關鍵字

數位電視地面波 ； 維特比解碼器 ； 通道狀態資訊 ； 軟式輸入

並列摘要

In the recent year, Orthogonal Frequency Division Multiplexing (OFDM) becomes the technique of the popular choice for the transmission. Because this technique can provide high data rate transmission within the bandwidth limit. Furthermore, in the multipath fading channel, it also have high performance by guard interval. Since the evolution of Digital Signal Processing, it has been used for many transmission systems such as DAB (digital audio broadcasting),DVB (digital video broadcasting), WLAN (wireless local area networking)…etc.
Previously, most researches about the performance of the Digital Video Broadcasting-terrestrial (DVB-T) systems are studied in hardware scheme and simulate in the channel environments assumed by researchers. Only a few of researches are researched by software and in the real channel environments. We keep on researching the previous program of the lab about DVB-T receiver. We’ll change the method of interpolation to calculate more accurate channel coefficients. And we will consider the channel state information into the metric to get higher performance. And we‘ll propose some problems that we will solve in the future.

並列關鍵字

OFDM ； DVB-T ； Viterbi decoder ； channel state information ； soft input

參考文獻

[1] Jan-Jaap van de Beek, “ML Estimation of Time and Frequency Offset in OFDM Systems,” IEEE Trans. Signal Process., vol. 45, no. 7, pp. 1800–1805, Jul. 1997.

[2] M. Speth, S. Fechtel, G. Fock and H. Meyr, “Optimum Receiver Design for Wireless Broad-Band Systems Using OFDM – Part I, “IEEE Trans. Commun., vol. 47, No. 11, Nov. 1999.

[3] M. Speth, S. Fechtel, G. Fock and H. Meyr, “Optimum Receiver Design for Design for OFDM-Base Broadband Transmission-Part II, “IEEE Trans. Commun., vol. 49, No. 4, Nov. 2001.

[4] Weon-Cheol Lee and Hyung-Mo Park, “Performance Analysis of Viterbi Decoder Using Channel State Information in COFDM System,” IEEE Trans. on Broadcasting, Vol.44.No.4,Dec. 1998, pp.488-496.

[7] 黃富生,” 數位電視內接收機同步系統之設計與實現,“國立中央大學博士論, 2006.